Investigating the Rates of Reactions

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Introduction

Investigating the Rates of Reactions Aim: My aim is to find out how concentration of water with sulphuric acid affects the rate of reaction when mixed with magnesium. Prediction: I predict that if the concentration of sulphuric acid to water is high, then the reaction will be quicker because there are more sulphuric acid particles in the solution for the magnesium particles to collide with. I also predict that the solution will give off hydrogen. The chemical reaction, which will take place is going to be exothermic as it will give out heat energy as it is reacting. Method: Firstly, I will half fill a water trough with water and will fill a measuring tube with water and invert it in the trough so that no water comes out. Then I will measure 1 molar of sulphuric acid, which will be 100ml and 3cm of a magnesium strip. I will put the sulphuric acid in a conical flask and then I will add the magnesium to the solvent. Quickly, I will put a rubber bung on the flask and will start the timer. As the rubber bung has a gas tube on it connected to the measuring tube, the reactants in the flask will let off hydrogen, which will go through the gas tube and into the measuring tube. ...read more.

Middle

They make the reactions faster but remain chemically unchanged themselves. Catalysts are important in industry as they allow manufacturers to produce products more rapidly. There are two types of catalysts, homogenous and heterogeneous. A homogenous catalyst is one that is in the same physical state as the reactant. A heterogeneous catalyst involves two physical states, such as a solid catalyst affecting a liquid reactant. Size of container: As liquids take the shape of their container, this will affect the rate of reaction. If a container is extremely large, the reactant particles will be extremely spaced out in the solvent and will have less chance of colliding with another particle as they might not have enough energy to travel that far. In a small container, the reactant particles would be close together and therefore would find it easy to collide with another particle. Apparatus: Conical Flask Magnesium Sulphuric Acid Water Measuring Tube (25ml) Rubber Bung connected with gas tube Water trough Timer Drawing of Set up: Results: Concentration of sulphuric acid Time taken for hydrogen to fill 25ml measuring tube (secs) Experiment 1 Time taken for hydrogen to fill 25ml measuring tube (secs) Experiment 2 100ml H2SO4, 1 molar 5.72 6.47 80ml H2SO4 and 20ml H2O, 0.8 molar 8.72 8.74 60ml H2SO4 and 40ml H2O, 0.6 ...read more.

Conclusion

I think that the concentration of 0.2 molar of sulphuric acid, took such a long time to fill the measuring tube with hydrogen compared with the other molars, was because the amount of water was so high, it was hard for the sulphuric acid particles to collide with the magnesium particles. I think my method was good as it was able to let me find my answer to how concentration affects the rate of a reaction, accurately. Although, I would have improved the experiment by using a syringe to measure the amount of hydrogen because it would have been more accurate than the measuring tube. I also think that to get an even more accurate answer to my aim, I could have done the experiment again but using a different solvent instead of sulphuric acid such as hydrochloric acid. This would then mean that I would be able to find out if concentration affects rates of reaction even if I use a different solvent. If I wanted to take my investigation further, I would put a thermometer in the conical flask to find out if concentration also affects the temperature of the solution. I would also further my investigation by putting the flask on an electric weighing scale to see if concentration also affects the mass of the solution, as it might get heavier or lighter. ...read more.

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